Mao wants to know your location
Jokes aside.
The problem with landlords is exploitation. Their concept of ownership of land is that you own it so you can do whatever you want, in sense of exploiting it's resources or, in case of a house for example, renting it and expecting a revenue for doing nothing. They, the landlords, are parasites that want to get value from something without doing anything and people in the "western world" (using the term for broad clarification) justify that. All of this does not mean that a landlord cannot be a socialist and help the cause in some way, like Engels but he was a member of the capitalists. Still, without destroying the system that permits all of this, even if there are landlords that are indeed communists, the status quo will continue with all the exploitation that follows it.
Clarify me if I'm wrong comrades, please. I'm still always learning.
Like I said, a "communist landlord" could help the cause in some way and then, if a communist revolution happens, decide to take part in the land reforms and collectivisation of land. But that is a rarity, because the system imposes exploitation, so the majority of landlords would still be exploitative parasites.
Even if this is possible we should not get our hopes on that but on changing the system itself. For, if it exists a system that promotes exploitation we should change that and not attach ourselves to the notion of individualism, bacause the individuals don't make changes. The masses do.
Class struggle will continue for many years to come, but at the end, with the abolition of class and the creation of a classless society, there will be no such things as landlords or capitalists. The people will be truly free.